Wayback Diff

A Shiny app that retrieves archived versions of any URL from the Internet Archive Wayback Machine, plots the captures on a calendar, and lets you diff two versions side by side.

The main panel has two tabs: Calendar (browse and pick versions) and Diff (view the comparison).

What it does

1. Retrieve — queries the Wayback Machine CDX Server API for the most recent archived snapshots of a URL (no API key needed).

2. Calendar — plots captures on a calendar (one year at a time, trimmed to the snapshot date range) for comparison.

3. Diff — compare the two selected versions:

   • Visible text (HTML stripped) or raw source
   • Side-by-side or unified diff view

Content is fetched via the Wayback id_ endpoint, which returns the original archived bytes with no toolbar injection, so the diff reflects real changes.

How this differs from the Wayback Machine calendar

• Most recent N only — only the most recent "Max snapshots" captures are fetched; the Wayback calendar shows every capture. Raise the limit to reach further back.

The list can include redirect captures (e.g. 301) and warc/revisit records; those have no standalone body, so diffing them may show little or nothing.

Setup

python3 -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt

Run

shiny run app.py

Tests

pip install -r requirements-dev.txt
pytest

License

MIT